Star could hold clue to universe's secrets

A newly-discovered star's historically low level of iron should see it enter the history books.Image: AAP

Thirty five thousand light years away on the edge of the Milky Way is an anaemic star that scientists think could hold clues about the nature of the universe's first celestial objects.

The star, which has been formally dubbed by scientists SMSSJ160540.18 - 144323.1, or SMSSJ160 for short, lacks iron - way more iron that usually expected.

"This incredibly anaemic star has iron levels 1.5 million times lower than that of the Sun. That's like one drop of water in an Olympic swimming pool," Dr Thomas Nordlander from the Australian Research Council's Centre of Excellence in Sky Astrophysics said.

This low level of iron is evidence of a long hypothesised, but unobserved, set of massive stars that existed at the beginning of the universe, say researchers.

These stars are believed to have been made up of only hydrogen, lithium and helium - elements created in the immediate aftermath of the big bang.

They would have been hundreds of times bigger than the sun, would have exploded with incredible power.

Scientists hypothesise that they have all but disappeared, making them all but impossible to observe.

"The good news is we can study the first stars through their children - like the one we've discovered (SMSSJ160)," co-researcher Professor Martin Asplund said.

SMSSJ160 was formed just after one of the first stars exploded.

According to researchers, the explosion was small on astronomical scales, with the star only being ten times the size of the sun.

Most of the heavy elements created in the supernova fell back into the remnant neutron star - the collapsed core of the giant star - that was left behind.

But a small amount of newly-forged iron escaped the neutron star's gravitational pull and went on to make SMSSJ160.

It's because of this low lever of iron that researchers believe its the remnant of one of the first stars and a key piece of evidence suggesting that they existed.

Whether or not SMSSJ160's discovery will hold up as evidence in the years to come is yet to be seen, but with its historically low level of iron it's bound to enter the history books regardless.